Page 157 - Airplane Flying Handbook

Eights Along a Road

An eight along a road is a ground reference maneuver in which the ground track consists of two opposite 360° adjacent turns. An

imaginary line drawn through the center of each 360° turn is perpendicular to the straight-line ground reference (road, railroad tracks,

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fence line, pipeline right-of-way, etc.) as illustrated in Figure 7-7. Like the other ground reference maneuvers, the objective is

further develop division of attention while compensating for drift, maintaining orientation with ground references, and maintaining a

constant altitude.

Figure 7-7. Eights along a road.

Although eights along a road may be performed with the wind blowing parallel or perpendicular to the straight-line ground reference,

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only the perpendicular wind situation is explained since the principles involved are common each. The pilot should select a

straight-line ground reference that is perpendicular to the wind and position the airplane parallel to and directly above the straight-line

ground reference. Since this places the airplane in a crosswind position, the pilot should compensate for the wind drift with an

appropriate wind correction angle.

The following description is illustrated in Figure 7-7. The airplane is initially in a crosswind position, perpendicular to the wind, and

over the ground-based reference. The first turn should be to the right toward a downwind position starting with a steepening bank.

When the entry is made into the turn, it requires that the turn begin with a medium bank and gradually steepen to its maximum bank

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angle when the airplane is directly downwind. As the airplane turns from downwind crosswind, the bank angle needs be

gradually reduced since groundspeed is decreasing; however, 1/2 of the reduction in groundspeed occurs during the first 2/3 of the

turn from downwind to crosswind.

The pilot needs control the bank angle as well as the rate at which the bank angle is reduced so that the wind correction angle is
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correct. Assuming that the wind is coming from the right side of the airplane, the airplane heading should be slightly ahead f its

position over the ground. When the airplane completes the first 180° of ground track, it is directly crosswind, and the airplane should

be at the maximum wind correction angle.
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As the turn continued toward the upwind, the airplane’s groundspeed decreasing, which requires the pilot to reduce the bank

angle to slow the rate of turn. If the pilot does not reduce the bank angle, the continued high rate of turn would cause the turn to be

completed prematurely. Another way explain this effect is—the wind is drifting the airplane downwind at the same time its

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groundspeed is slowing. If the airplane has a steeper-than-required bank angle, its rate of turn will be too fast and the airplane will

complete the turn before it has had time to return to the ground reference.

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